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101.
Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4 g/kg body weight B. papyrifera and B. carterii daily for 120 days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens.  相似文献   
102.
Returning honey bee foragers perform waggle dances to inform nestmate foragers about the presence, location and odour of profitable food sources and new nest sites. The aim of this study is to investigate how the characteristics of waggle dances for natural food sources and environmental factors affect dance follower behaviour. Because food source profitability tends to decrease with increasing foraging distance, we hypothesised that the attractiveness of a dance, measured as the number of dance followers and their attendance, decreases with increasing distance to the advertised food location. Additionally, we determined whether time of year and dance signal noise, quantified as the variation in waggle run direction and duration, affect dance follower behaviour. Our results suggest that bees follow fewer waggle runs as the food source distance increases, but that they invest more time in following each dance. This is because waggle run duration increases with increasing foraging distance. Followers responded to increased angular noise in dances indicating more distant food sources by following more waggle runs per dance than when angular noise was low. The number of dance followers per dancing bee was also affected by the time of year and varied among colonies. Our results provide evidence that both noise in the message, that is variation in the direction component, and the message itself, that is the distance of the advertised food location, affect dance following. These results indicate that dance followers may pay attention to the costs and benefits associated with using dance information.  相似文献   
103.
Skin-lightening creams are extensively promoted online and in the media. They may contain a wide variety of active ingredients such as mercury, hydroquinone, and steroids that are highly toxic, especially after prolonged application. For more than a decade, we found high mercury content in many products sold on Saudi markets. Some of these products were later banned by the government. However, the presence of other ingredients has not been documented. We undertake this study on some of the most popular skin-lightening creams on the market to test for toxic ingredients such as mercury, titanium dioxide, hydroquinone, and corticosteroids. A total of 33 different brands were selected for the analysis of titanium (50 samples), hydroquinone (55 samples), and corticosteroids (56 samples) with the exception of mercury in which only 23 brands (34 samples) were tested. This study showed that 2 of 34 skin-lightening creams had mercury above the US FDA limit of 1?µg?g?1. All products had titanium dioxide at less than 25% (w/w) of the EU and US FDA safety limits for personal products but 8 products from 7 different brands contained titanium dioxide above 1%, the permissible limit in cosmetics as color additives. In this study, we found 8 creams from 7 different brands had hydroquinone above 1.5% (w/w), the newly proposed FDA limit of hydroquinone in OTC skin-lightening drug products. Among the four tested corticosteroid compounds, the most frequently detected was cortisone and 18 products from 13 different brands were above 6?µg?g?1 (MDL) with a maximum of up to 0.32% (w/w). Dexamethasone was found in 7 creams from 5 different brands with only 3 above the MDL of 9?µg?g?1. Although one might argue that these corticosteroids are of mild or low potency, and they may be unlikely to have any adverse effects, these products are marketed as personal-care products on the assumption that they are safe and free of steroids. The overall results indicate that many of the skin-lightening creams sold in the Saudi market contained one or more toxic ingredients that in most cases were not listed on the packaging. Many of these ingredients are harmful and pose health risks if we take into account the frequency of application, the duration of practice, and area of the body applied, and their use during pregnancy and/or periods of lactation.  相似文献   
104.
Environmental Chemistry Letters - Membrane separation technology has become one of the most frequently used techniques to secure adequate water resources for human consumption and other...  相似文献   
105.
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are mutagenic, carcinogenic, and toxic to living organisms. Here, the ability and effectiveness of selected bacteria isolated from an oil‐contaminated area in biodegrading PAHs were evaluated, and the optimal conditions conducive to bacterial PAH biodegradation were determined. Of six bacterial isolates identified based on their 16S rRNA sequences, Planomicrobium alkanoclasticum could subsist on and consume nearly all hydrocarbons according to the 2,6‐dichlorophenolindophenol assay. The efficacy of this isolate at PAH biodegradation was then empirically confirmed. After 30 days of incubation, P. alkanoclasticum degraded 90.8% of the 16 PAH compounds analyzed and fully degraded eight of them. The optimum P. alkanoclasticum growth conditions were 35°C, pH 7.5, and NaNO3 as the nitrogen source. Under these biostimulant conditions, P. alkanoclasticum degraded 91.4% of the total PAH concentration and completely decomposed seven PAHs after 15 days incubation. Hence, P. alkanoclasticum is an apt candidate for the biodegradation of PAHs and the bioremediation of sites contaminated by them.  相似文献   
106.
Recently developed shopping centres have become one of the main features of shopping activities in Jeddah. In fact the city of Jeddah experienced a surprising increase in the development of shopping centres during the last decade. Developers entered the land development process with the intention of realising profits from a long‐term investment, but a considerable number of shopping centres were developed on the basis of insufficient or no feasibility studies thereby underestimating or neglecting expected rate of return and occupancy. Spatially, shopping centres present distinctive spatial and rental value patterns. This article is concerned with explaining the supply side of shopping centres by examining the development process through which they were built. The analytical framework is based on discussing the interaction of three sets of variables: contextual factors, including land policy and market mechanisms; site characteristics, and the developer's characteristics.  相似文献   
107.
通过对南方某省1988~1992年工伤发生情况的调查,五年间工伤事故数、工伤死亡率及重伤率有逐年增加的趋势,煤炭、交通、建筑三个行业的工伤死亡人数约占工伤死亡总数的50%;县以下乡镇企业中的工伤事故数、死亡率及重伤率均居首位。工伤事故中造成死亡的原因主要集中在物体打击、触电、高空坠落;引起重伤的原因集中在机械伤害、物体打击、车辆伤害和高空坠落。因此在劳动安全卫生管理工作上,要采取一些强有力的干预措施,特别要加强对乡镇工业企业及那些易发生工伤事故企业的管理。  相似文献   
108.
109.
When deciding how to conserve biodiversity, practitioners navigate diverse missions, sometimes conflicting approaches, and uncertain trade-offs. These choices are based not only on evidence, funders’ priorities, stakeholders’ interests, and policies, but also on practitioners’ personal experiences, backgrounds, and values. Calls for greater reflexivity—an individual or group's ability to examine themselves in relation to their actions and interactions with others—have appeared in the conservation science literature. But what role does reflexivity play in conservation practice? We explored how self-reflection can shape how individuals and groups conserve nature. To provide examples of reflexivity in conservation practice, we conducted a year-long series of workshop discussions and online exchanges. During these, we examined cases from the peer-reviewed and gray literature, our own experiences, and conversations with 10 experts. Reflexivity among practitioners spanned individual and collective levels and informal and formal settings. Reflexivity also encompassed diverse themes, including practitioners’ values, emotional struggles, social identities, training, cultural backgrounds, and experiences of success and failure. Reflexive processes also have limitations, dangers, and costs. Informal and institutionalized reflexivity requires allocation of limited time and resources, can be hard to put into practice, and alone cannot solve conservation challenges. Yet, when intentionally undertaken, reflexive processes might be integrated into adaptive management cycles at multiple points, helping conservation practitioners better reach their goals. Reflexivity could also play a more transformative role in conservation by motivating practitioners to reevaluate their goals and methods entirely. Reflexivity might help the conservation movement imagine and thus work toward a better world for wildlife, people, and the conservation sector itself.  相似文献   
110.
The recent development of infrastructure all around the world has resulted in an increasing trend of online examination in universities. The paper is an approach in theory and practical aimed at analyzing the feasibility of sustainable examination in four universities and its environmental impact reducing the paper use terming it as green examination. The paper studied the integration of sustainability through the use of computers and technology in the examination of the universities viz. King Khalid University (KKU), Saudi Arabia, Integral University (IU), India, Aligarh Muslim University (AMU), India, and The Hague University (HU), The Netherlands. The study has analyzed the trend of paper requirement, paper utilized and paper wasted in all the four universities. The environmental impact resulting from reduced paper use has been also analyzed. The feasibility of e-examination, its implementation and the implications has been undertaken in the study. The study concludes that the e-examination can almost make the examinations paperless and feasible in the four universities.  相似文献   
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